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What is the atomic number of the element that has the electronic configuration 2, 8, 5?
13
14
15
16
15
The atomic number of an atom is defined as the total number of protons in its nucleus, which is equal to the total number of electrons in a neutral atom. By summing the electrons in the shells (2 + 8 + 5), we arrive at a total of 15 electrons, indicating an atomic number of 15.
The atomic number of an atom is defined as the total number of protons in its nucleus, which is equal to the total number of electrons in a neutral atom. By summing the electrons in the shells (2 + 8 + 5), we arrive at a total of 15 electrons, indicating an atomic number of 15.
Think of an atomic number like a house address: if the 'number of people' living in the house (electrons) is 15, the house address is assigned as 15.
Z=NpтАЛ=NeтАЛ тАФ where Z is atomic number, NpтАЛ is number of protons, and NeтАЛ is number of electrons.
According to the Bohr-Bury scheme, electrons fill energy shells designated as K, L, M, etc. The electronic configuration 2,8,5 represents the distribution of 15 electrons in the K (n=1), L (n=2), and M (n=3) shells respectively. The total electron count Z=тИСeтИТ=15 corresponds to the element Phosphorus.
The electronic configuration 2,8,5 belongs to the element Phosphorus (P).
Phosphorus belongs to Group 15 and Period 3 of the periodic table.
The valence shell here is the M-shell, which contains 5 valence electrons.
Predicts chemical reactivity and valency.
This model does not account for subshell (s, p, d, f) energy level variations.
Used to identify elements in the periodic table.
Used to determine the valency and bonding characteristics of atoms.
The element with atomic number 15 is Phosphorus, a non-metal.
Option A (13) corresponds to Aluminium (2,8,3), Option B (14) corresponds to Silicon (2,8,4), and Option D (16) corresponds to Sulfur (2,8,6).
C is correct тАФ The total number of electrons in a neutral atom is equal to the sum of the electrons in each shell, which equals 15.
For any configuration question, simply sum the digits to find the atomic number; if the sum is Z>20, remember that subshell filling (4s before 3d) becomes necessary.
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